You can’t boost your immune system with supplements—here’s what you can do

Vitamins and supplements like zinc and cod liver oil are often touted for their ability to boost your immune system, but Jeffrey Bland, the “father of functional medicine,” says that’s not actually possible.

“I’ve heard, ‘I can boost my immune system if I take a lot of vitamins.’ It could be vitamin D, vitamin A [or] zinc,” Bland says. “[But] those nutrients don’t boost the immune system. Those nutrients may fill the gaps in a person who needs them to meet their daily requirements for proper immune function, but you’re not going to boost the immune system like you do with a vaccination.”

Getting vaccinated causes a physiological effect that boosts the function of the immune system. Supplementing with nutrients doesn’t have the same effect, he says.

Instead of a sole focus on boosting immunity, Bland says you should be thinking about rejuvenation. Roughly every four months, the cells that make up our immune systems are replaced with new cells.

“The question I ask people is, ‘Do you want the cells that are replacing the ones today to be as good as, better than, or worse than the ones that you have 1742660816?'” he tells CNBC Make It.

While you should always consult your doctor about your specific health needs, Bland, who is also the president and CEO of Personalized Lifestyle Medicine Institute, has a few practices he suggests for rejuvenating your immune system.

1. Stick to a Mediterranean diet: Follow an eating pattern that is rich in plant foods like colorful fruits and vegetables, virgin olive oil and natural meats and fish, Bland says.
2. Prioritize good quality sleep: “During sleep, our body undergoes this rejuvenation,” he says. Make sure your sleep duration and quality are at optimal levels, and have a great night time routine that lowers your stress levels before you go to bed so you can properly rest.
3. Get at least a half hour of physical activity a day: You can choose to move you body through dance, aerobic exercise or even walking, he says. “We’re not talking about anything that’s extreme. We’re talking about things that can be done daily and make big differences in your immune system’s outcome.”
4. Drink enough water daily: Have at least two to three glasses of water, or 25 to 30 ounces, a day because “it allows your body to get things in and out properly,” he says.
5. Nurture the relationships in your life: “What we recognize is that your immune system can smile, it can laugh, have fun, it can be part of the best of you, but it can also cry and be sad,” he says. Having good quality relationships in your life that make you feel optimistic and loved has a positive effect on your immune system.

“Those are some simple tips. Try to think about them every day and apply them,” Bland says. “[It] can make significant differences in your immune capability.”

Want to earn some extra money on the side? Take CNBC’s new online course How to Start a Side Hustle to learn tips to get started and strategies for success from top side hustle experts. Sign up today and use coupon code EARLYBIRD for an introductory discount of 30% off $97 (+taxes and fees) through April 1, 2025.

Plus, sign up for CNBC Make It’s newsletter to get tips and tricks for success at work, with money and in life.